Advanced Materials Research Vols. 718-720

Abstract: In this paper features of structure at the atomic level, magnetic properties, and mechanisms of structural relaxation during thermal annealing of melt-spun ribbon Fe₆₆Co₂₄Si₃B₇ (ribbon thickness is 28 microns) will be discussed. By means of differential scanning calorimetry and X-ray diffraction analysis of melt-spun alloy it has been shown that structural relaxation processes have complex multi-step nature, primarily related with instability of alloy. Using this data it has been shown that magnetic structure-sensitive properties, such as coercivity and magnetic moment, can be considered as structural relaxation indicators in amorphous alloys. The original amorphous material when heated to crystallization temperature partially passes to the crystalline state, causing the increase in residual magnetic moment and coercivity.

Abstract: We describe the non-harmonic dipole moment resulting of the interaction between a set of nanoparticles randomly distributed with a linear polarized plane wave. The study is performed by considering its structural parameters as function of time establishing a mechanical analogy with a spring less system. The simplest case occurs for two nanoparticles and the Mathieu differential equation describes the dipole interaction, from which interesting resonance effects are predicted. We show that an effective refractive index depending of time is obtained having the possibility to take negative values which offers interesting applications in the development of metamaterials. Finally associating a catastrophe function for the phase function, during the emission process we are able to describe the width of the frequency spectrum. The theoretical are well agree with experimental results previously reported in the optical literature.

Abstract: Corrosion experiments were carried out with metals 20G, 15CrMoG and 12Cr1MoVG under the simulated atmosphere (N₂-5%O₂-1500μL/L HCl) of superheaters in waste plastic boilers to choose appropriate materials preventing high temperature corrosion. Corrosion dynamic curves were plotted by mass gain per unit area. Metal specimens after corrosion tests were analyzed by SEM-EDS and XRD. The results show that 20G has the poorest anti-corrosion abilities among the three materials; the corrosion process is involved in activation oxidation of chlorine. Addition of Cr in alloys can improve their corrosion resistance in the mixed atmosphere.

Abstract: Using the standard microcanonical molecular-dynamics method, the behaviors of the individual atoms in the LJ clusters are investigated. It is found that the characteristics of the long-time averaged kinetic energy of the individual atom in the solid-like clusters are related with the symmetry of the clusters. Different symmetries result in different kinetic energy distributions over the atoms of the clusters.

Abstract: The natural fibre composite materials are nowadays playing a vital role in replacing the conventional and synthetic materials for industrial applications. This paper proposes a natural fiber composite made of Abaca fibre as reinforcing agent with Epoxy resin as the matrix, manufactured using Hand Lay-up method. Glass Fiber Reinforced Plastics (woven rovings) are used to improve the surface finish and impart more strength and stiffness to natural fibers. In this work, the fibers are arranged in alternative layers of abaca in horizontal and vertical orientation. The mechanical properties of the composite are determined by testing the samples for tensile and flexural strength. It is observed that the tensile strength of the composite material is dependent on the strength of the natural fiber and also on the interfacial adhesion between the reinforcement and the matrix. The composite is developed for automobile dashboard/mudguard application. It may also be extended to biomedical, electronics and sports goods manufacturing. It can also be used in marine products due to excellent resistance of abaca to salt water damage since the tensile strength when it is wet.

Abstract: The critical phenomena on cobalt monolayer films were studied by means of computersimulation. Proposed approach on the base of data of scanning tunneling microscopy gives possibilityestimate of critical concentration needed for concentration transition into ferromagnetic state. Assumptionabout presence of critical switching field allowed simulated hysteresis loops for given 1.5,2.0, 2.5 and 3.0 ML cobalt samples in frame of Ising model, which ones have qualitative agreementwith magnetometric data.

Abstract: Paper presents results of experiments on spontaneous ignition behaviour of dust accumulations in air as well as in atmospheres with enriched nitrogen content.

Abstract: An analysis based on scanning electron microscopy coupled with EBSD system unveiled the absence of morphological texture in hot deformed and annealed AZ31 alloy. Samples of industrial AZ31 alloys have undergone two deformation types (hot rolling and hot uniaxial compression). We have evidenced the absence of any correlation between the morphological parameters (shape coefficient and standardized equivalent diameter) and the basal type crystallographic texture dominated (the {0001} basal plane being parallel to the normal direction and to the intended compression direction).

Abstract: In this paper a method of characterization of network structures with multiscale hierachical periodicity in the spectral representation is suggested. The informodynamic analyses of the degree of similarity of complicated systems with different level of organization was established as the result of convolution of diffraction patterns. The indicator of the fractal dimension as the characteristic of degree of ordering of mesodefect systems of planar media was introduced. It is established that the rejection of the fractal dimension is observed under the increasing stochasticity of network system.

Abstract: In this paper, method and device Used for evaluating the contamination condition on the surface of composite insulator was proposed. The method proposed in this paper considered the hydrophobicity and pollution degree on the surface of composite insulator at the same time. Under the condition of different basic Salt deposit density and different migration time the suitability of dissolution Salt deposit density method was studied. The test results show that the dissolution Salt deposit density with the increasing of migration time gradually reduced at the same basic Salt deposit density. The dissolution salt deposit density with the increasing of basic Salt deposit density gradually increases at the same migration time. It is found that the dissolution salt deposit density method proposed in this paper can well evaluate the contamination condition on the surface of composite insulator.